[Show abstract][Hide abstract] ABSTRACT: The presence of bi-articular muscles in tetrapod limbs has created an enigmatic paradox. When the rectus femoris acts alone, knee is extended but hip is flexed. When the hamstering acts alone, knee is flexed but hip is extended. When both muscles act together, however, they act as a braking against each other for one joint whereas they act coordinately for another joint. To solve the paradox and examaine functional roles of and motion control over mono- and bi-articular muscles, biomechanical studies have been performed on human arms and legs. The results were also tested using experimental robotic analyses. As we have proposed a coordinated motion control model, the results have demonstrated that three antagonistic pairs of six mono- and bi-articular muscles control coordinately output force and force direction at the wrist or ankle, perform weight-bearing motion and maintain stable posture. These antagonistic muscles are defined as functionally different effective muscular system (FEMS) of the two-joint link mechanism. Based on anatomical and/or functional studies of basal vertebrates including amphioxus, mudskippers (teleosts), Latimeria (coelacanth) and lungfishes, we have further investigated the origin and evolution of FEMS in vertebrates. We will present the results and discuss the model, particularly by focusing on the contact-task during a fish to tetrapod transition in the Devonian.
[Show abstract][Hide abstract] ABSTRACT: We examined the effects of chicken egg hydrolysate (also known as "bone peptide" or BP) on bone metabolism in 5- to 8-month-old orchidectomized dogs. The bone formation marker serum bone alkaline phosphatase (BAP) and the bone resorption marker urine deoxypyridinoline (DPD) were used as indicators to measure changes in bone metabolism. The following results were observed that Serum BAP was higher in dogs fed BP-enriched food throughout the clinical investigation. Serum BAP was statistically significantly higher in dogs fed BP-enriched food than in dogs fed non-BP-enriched food at 2 months after orchidectomy. This suggests that BP promoted bone formation immediately after orchidectomy.
Journal of Veterinary Medical Science 01/2015; 77(4). DOI:10.1292/jvms.13-0421 · 0.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In small animal veterinary practices, body condition score (BCS) is generally
used to diagnose obesity. However, BCS does not constitute objective data. In this study,
we investigated the value of using human body fat analysis software for male dogs. We also
compared changes in body fat after neutering. Changes in body fat at the time of neutering
(age 1 year) and 1 year later were compared by performing CT scanning and using human body
fat analysis software. We found that body fat increased in all the individuals tested. In
terms of the site of fat accumulation, subcutaneous fat was more pronounced than visceral
fat with a marked increase on the dorsal side of the abdomen rather than the thorax.
Journal of Veterinary Medical Science 11/2013; 76(3). DOI:10.1292/jvms.13-0397 · 0.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The cervical and thoracic regions including vertebrae, spinal nerves, and brachial plexus were examined by macroscopic and three-dimensional computed tomography observational scans in the two-toed sloth (Choloepus didactylus). This species possesses seven cervical vertebrae unlike closely related sloths, which possess varying number of cervical vertebrae ranging from five to ten. The large axis and the partially vestigial third cervical vertebra are morphologically characteristic of C. didactylus. In addition, the spinal nerve branches of C5, C6, C7, C8, and T1 contributed to the brachial plexus, whereas C4 and T2 did not supply nerves to the plexus. Histological data showed that the branches of C5, C6, C7, and C8 were obviously thicker than that of C4 and T1. The most notable observation was that only the two-toed sloth unlike other sloth species is conservative in these morphological characteristics regarding the cervical vertebrae spinal nerves. By comparing the morphological patterns of the cervical and thoracic spine and the brachial plexus of the two-toed sloth with ancestral morphological patterns and related species, which have derived a repatterned and variable morphology of these structures, it is possible to elucidate the morphological evolution of the cervical and thoracic regions in the evolutionary history of these mammals.
Mammal Study 09/2013; 38(3):217-224. DOI:10.3106/041.038.0310 · 0.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study, we explored the relationship between brain volume and brain width in a wide range of extant mammals and birds in an effort to determine whether brain width could be used as an appropriate variable for estimating the brain volume of extinct species. The relationship between brain volume and brain width in extant species was assessed using computed tomography images of mammalian skulls from 55 species representing 13 orders, and avian skulls from 64 species representing 21 orders. Brain volume and brain width showed a strong linear correlation in both mammals and birds. We also discovered that brain volume of extant as well as extinct mammals and birds can be estimated on the basis of brain width. The brain widths of Cynodontia, Triconodonta, and non-avian Theropoda were relatively narrower than those of extant mammals and birds. This data indicates that compared to their early ancestors, the brain width of both mammals and birds has increased with respect to brain endocast volume. Thus, on the basis of our results we have concluded that the relationship between brain volume and brain width is useful for estimating the brain volume of extinct mammals and birds. In addition, it was found that relative brain width of both mammals and birds has increased throughout their evolutionary history from early ancestors to extant species.
Paleontological Research 08/2013; 17(3):282-293. DOI:10.2517/1342-8144-17.3.282 · 0.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The electrocardiogram of nonhuman primates is similar to that of humans because of similar intrathoracic heart position and structure. Despite the frequent use of nonhuman primates in biologic studies, few electrocardiographic studies of Japanese monkeys (Macaca fusucata) have been reported, and no reference data are available for this species. We obtained limb-lead electrocardiograms from indoor-bred and housed ketamine-sedated Japanese macaques (48 male; 56 female; mean age, 44.3 mo; mean body weight, 4.84 kg) in the dorsal recumbency. The following quantitative data was obtained: heart rate, P wave amplitude and width, R wave amplitude, QRS duration, PR interval, QT interval, T wave height, and mean electrical axis. Corrected QT intervals were calculated by using the Bazett and Fridericia formulae. Measurements were evaluated according to sex and age. The duration of the QRS complex showed moderate correlation with age in male monkeys. All parameters, except heart rate, were similar to previous reports from Japanese, cynomolgus, and other macaques. P waves, R waves and mean electrical axis did not differ significantly between humans and Japanese macaques, but the wave amplitude in macaques was half that in humans. Our electrocardiographic measurements can serve as normal reference data for sedated, young Japanese monkeys.
Journal of the American Association for Laboratory Animal Science: JAALAS 07/2013; 52(4):491-494. · 1.12 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Neuronal ceroid lipofuscinosis (NCL) is an inherited, neurodegenerative lysosomal disease that causes premature death. The present study describes the clinical and molecular epidemiologic findings of NCL in Border Collies in Japan for 12 years, between 2000 and 2011. The number of affected dogs was surveyed, and their clinical characteristics were analyzed. In 4 kennels with affected dogs, the dogs were genotyped. The genetic relationships of all affected dogs and carriers identified were analyzed. The survey revealed 27 affected dogs, but there was a decreasing trend at the end of the study period. The clinical characteristics of these affected dogs were updated in detail. The genotyping survey demonstrated a high mutant allele frequency in examined kennels (34.8%). The pedigree analysis demonstrated that all affected dogs and carriers in Japan are related to some presumptive carriers imported from Oceania and having a common ancestor. The current high prevalence in Japan might be due to an overuse of these carriers by breeders without any knowledge of the disease. For NCL control and prevention, it is necessary to examine all breeding dogs, especially in kennels with a high prevalence. Such endeavors will reduce NCL prevalence and may already be contributing to the recent decreasing trend in Japan.
The Scientific World Journal 07/2012; 2012(1):383174. DOI:10.1100/2012/383174 · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The musculoskeletal system of the aardvark (Orycteropus afer) tail was morphologically examined in two adult specimens. The tail musculature comprised three muscular groups, viz. a dorsal sacrocaudal system that consisted of the irregularly oriented Musculus sacrocaudalis dorsalis medialis and M. sacrocaudalis dorsalis lateralis, a lateral inter-vertebral connecting system, and a ventral sacrocaudal system characterized by the thick M. sacrocaudalis ventralis lateralis and M. sacrocaudalis ventralis medialis. Both the dorsal and ventral systems possessed large tendon groups that strengthened the tail structure. Computed tomography (CT) examination showed the presence of large but homogeneous cartilaginous inter-vertebral discs, whereas V-shaped bones were situated at the ventral aspect of the caudal vertebrae at the level of the inter-vertebral discs. CT visualization of the tendons and V-shaped bones in various tail positions suggested that these structures contribute to the tunnel digging action by bearing the trunk weight and lending force when the aardvark are displacing the soil by means of the forelimbs.
[Show abstract][Hide abstract] ABSTRACT: With 12 figures and 3 tables
The coxa of palaeognaths including extinct aepyornithid species was compared by means of osteology, computed tomography (CT) imaging and macroscopic anatomy. The pre-acetabular area of the ilium was proportionally much larger in width and height in aepyornithid species than in other extant palaeognaths. The post-acetabular area of the ilium, ischium and pubis was relatively short and bilaterally extended in aepyornithid species. Although the Aepyornis species might have produced egg with a major axis exceeding 300 mm in major axis, the short post-acetabular coxa and widely opened ischium and pubis would not have been able to stably hold the eggs in the posterior space of the pelvic cavity unlike the situation in the ostrich. As aepyornithid species resembled the kiwi in measurement ratios of length and width in the pre-acetabular area, a functional–morphological model of the coxa in the aepyornithid species can be proposed based on that of the kiwi. From our data, we suggest that the extinct species of Aepyornis and Mullerornis species effectively used the anterior space of the pelvic cavity to support their extraordinary large egg.
[Show abstract][Hide abstract] ABSTRACT: In terrestrial mammals, the surface molecule CD34 is used as a marker to identify hematopoietic progenitor cells. To clarify whether CD34 expression can be used to confirm the undifferentiated state of hematopoietic-like cells isolated from the bone marrow of bottlenose dolphin, Tursiops truncates, we determined in this study the sequence of dolphin CD34 cDNA and analyzed its mRNA expression. Dolphin CD34 cDNA can be expressed as two forms, one that encodes a full-length version and a variant, truncated version of the gene. Both forms were detected in bone marrow mononuclear cells and in various tissues using RT-PCR. The truncated form was not detected in peripheral blood mononuclear cells, and neither form was detected in polymorphonuclear leukocytes. This is the first report on CD34 in marine mammals and our results suggest that dolphin CD34 may be a useful marker to identify hematopoietic progenitor cells.